It is probably difficult to prescribe a specific turbulence model for some type of flows in general circumstances. I see than you already have decided to use a two-equation model, which I would assume there might be some elements you have considered which have led to this conclusion. Generally speaking there is no "better or worse" turbulence model, unless you consider 1-the influence of the specific turbulence model on your problem, 2-some flow characteristics which may be important to you or more important anyway. 3-economy:computational time and 4-the universality of the empirical coeffficients, as they may entirely rule out some very attractive models. I would suggest that you probably hight light the elements of your interest in the flow characteristics and then it would be easier to choose the appropriate model. If the model is to be applied to real cases and is not part of a purely academic research project, the conventional models may be more promising.